Rotary engine



May 19, 1931. VN. D. LEV!N 1,805,875

ROTARY ENGINE Original Filed Feb 13, 1917 2 Sheets-Sheet 1 I O J .3

Patented May 19, 1931 l UN rED. stares te eFFwx NlfLS D. LEVIN, FGOLUIVIBUSQOHIO, ASSIGNQR TO THE JEFFREY MANUFACTURING COMPANY, orconstra ns, onto, A eenroaarrcn' or onIo ROTARY ENGINE Application filedFebruary 13, 1917', Serial E'o. 453,715. Renewed March 19, 1921;

This invention relates to certain newv and useful improvements in rotaryenginesand especially to that class of engine in which .a pairofparallel rotors having inter-meshlng tooth blades are mounted inacasing the walls of which cooperate to confine the actuating fluid tothe spacesbetween the blades of the rotors.

tinued rotation after the supply The especial object is to provide anengine of the class described, of high efficiency, great durability, andextreme compactness ofdesign, which shall be especially adapted to useunder the exacting conditions obtained in machines for mining coal. V

.Another object is to provide improved mcthod of constructing the rotorsandof mounting the same in the engine casing. Another object is toprovide means to prevent-the formation ofa vacuumon the admission sideof the rotors during their. conof actuating fluid has been shut off. 7 I

These and other objects will appear in the following specificationwherein is disclosed disclosed in Fig. 1.

Fig. 3 is a transverse SQCblOIl along the line 33 of Fig. 2. I

Fig. 4: is a transverse section alongthe line 44 of Fig. 1.

I Fig. 5 is an elevation oftheforward end of the en ine illustrated inFig. 1. 1

Fig. 6 is a plan view, partly in sectlon, offa modified form of myinvention, the upper portion of the casing being broken away to revealthe interior parts of the engine. 1

Like numerals refer to similar parts 1n the several figures.-

, The preferred embodiment of my inventi-on comprises a casing 37 uponwhich are formed lugs 38 by which it may be attached to any preferredfoundation, Withinthis casin closely approaches the tops of thespiraltooth blades 41 on both sides of the central longi- Fig. 2 is a:side elevation of the machine casing is mounted a pair of similarparallel drums to their. ends and extending around a part of theircircumference. Thesedrums are mounted upon parallel shafts 42 and 43 towhich are clamped the inner races of the ball bearings 4C4: and-4L5 bysuitable clamping members 46 and 4-7 The outer races of the.

ball bearings 44 and 45 are supported in recesses 48 and 49 of the endplates 50. and 51 secured to the casingby suitable machine screws 52 tosupport the rotor.

The casing 3 7 entirely encloses the rotors 39 and 40 and is provided atits upper. side with aninspection window 53 having a cover plate 54secured in place by suitable machine screws 55. The upper portion of thecasing forms an exhaust chamber 56 which receives the fully expandedactuating fluid and discharges itinto the atmospherethrough the exhaustopenings 57 at either side of the The lower wall 58 ofthe casing tudinalplanes of the casing for a distance equal to the'spiral advance of thetooth blades.

.i'lfhis surface 58 cooperates withthe tooth blades to form Vshaped-expansion chambers ,59 adapted to receive the actuating fluidfrom the port 60 positioned in the central longitudinalplane of thecasing. This port GOIis of such proportions that the admission of fluidto each expansion chamber is cut off bythe succeeding tooth blades assoon as said chamber has received its. initial charge. As the surface 58extends only a dlstance equal to the spiral advance of the tooth veinctlthis chambers at the instant when it is expanded tothe full effectivelimit. It is, therefore,

unnecessary for the end walls of ,thecasing satisfactory operation ofthe journal bearings and, at the same time, assist in the quick reliefof the pressure in the expanslon chainfluid will be exhausted from theexpansion bers. Formed in the lower wall of the casing is an admissionchamber 62 communicating with the port and provided at either side ofthe casing with screw threaded apertures 63 and 64 into which may befitted the supply pipe 65'through which the actuating fluid is receivedfrom the source of fluid supply. The aperture 64 on the side of themachine opposite the supply pipe 65 may be closed in, any convenientmanner, as by a pipe plug 66 to prevent the escape of the actuatingfluid. A suitable throttle valve may be connected in the supplypipe 65at a point convenient to the hand of the operator, affording means tocontrol the supply of actuating fluid to the engine. When fluid isadmitted into the chamber 62 it flows through the port 60 into'the'su'ccessive expansion chambers 59 cansing the rotors 39 and 40 torevolve in opposite directions. Vhile the engine is in operation thepressure of the air in the admission chamber 62 and in the expansionchambers 59 tends to lift the rotors 39 and 40 away from the casingsurface 58 thereby preventing actual contact of the metal of the rotorswith that of the casing. Should the rotation of the drums '39 and 40 becontinued after the in the admission and expansion chambers therebypermitting the rotors 39 and 40 to be forced against the casing wall 58by the atmospheric pressure, producing excessive friction between therotor teeth 41 and the "casing wall 58 and striking sparks therefromwhich escape through the exhaust openings 57. Mining machinery is oftensurrounded by a gaseous atmosphere adapted to ignition by such sparksand I have, therefore, provided relief devices to prevent the formationof such vacuums. Formed in the side wall of the casing is an aperture 68communicating with the admission chamber 62, into which is fitted therelief valve 69. This relief valve comprises a metallic ring 7 O,secured to the casing by suitable machine screws 71, the inner edge ofwhich is beveled to form the valveseat 72. Upon this valve seat 72 isfitted a valve disc 7 3' having a central stem'7 4 adapted to.longitudinal movement in a guide block 75supported centrally of the ring70. To the outer end of the valve stem 74 is secured a a: collar 76engaging the outward end of a comfluid from the admission chamber 62.Should the pressure within the admission chamber become less than thatof the surrounding atmos. here the valve disc 73 will be pressedinwardly to allow inflow of the atmosphere to which they are controlled.

equalize the pressure thereby preventing the undesirable frictionbetween the rotor teeth and the casing and the consequent productionof'sparks.

At one end of the engine the shafts 42 and 43 project beyond thebearings 44 to form the shaft extensions 78 and 79. Upon these shaftextensions are mounted two similar spur pinions 80 and 81 slidablelongitudinally there of and connected rotatively therewith by suitablefeather keys 82. The pinions 80 and 81 are provided with circumferentialgrooves 83 adapted to engage suitable shifting collars 84 for connectionwith the shifting devices by which the position of the pinionlongitudinally of the shaft extension may be controlled. A suitable gearhousing 85 is attached to the end plate 50 and completely encloses thesepinions and the devices by Mounted in a journal bearing 86 of the gearhousing 85, extending longitudinallyin the central planes of the casing,is a shaft 87 to the projecting end ofwhich is attached a clutch member12 by which the rotative parts of the engine are connected to drive. anypreferred transmission mechanism, as for example, that connected withthe cutting mechanism of a mining machine. 7 At the inner end of theshaft 87 is a spur gear 88 adapted to mesh with the spur pinions 80 and81 when they are at the inner end of their movement along the shafts 78and 79. The width of the gear 88 is such, however, that when the saidpinions are at the outer limit of their movement they will be out ofengagement with said gear. Mounted in bearings of the gear housing 85 isa transverse shaft 89 to which is attached a pair of rocker arms 90having apertures engaging the trunnions 91 of the shifting collar 84which engages the groove 83 in the pinion 80. Rotatable upon the shaft89 is a quill 92 to which is attached a pair of rocker arms 93 havingapertures engaging the trunnions 91 of the shifting collars 84 whichengages the groove 83 of the pinion 81. The

shaft 89 and quill 92 project beyond the bearing 85a and to theirprojecting ends are attached rocker arms 94 and 95 respectively. Tothese rocker arms are connected the rods 96 and 97 which extend to apoint convenient to the hand of the operator. By the manipulation ofthese operating rods 96 and 97 the shaft 89 and quill 92- may be rotatedto oscillate the rocker arms 90 and 93 to shift the pinions 80- and 81into or out of engagement with the gear wheel '88. As the rotors 39 and40 revolve in opposite direction it necessarily follows that thedirection of rotation of the shaft 87 will depend upon which of thepinions 39 and 40 is in engagement with the wheel 88. By thisarrangement means is afforded to drive the shaft 87 and the machineryconnected therewith in either direction or to entirely disconnect itfrom the ro tatingparts of theengine. 1

bearings 101 and 1020f a gear housing 103 attached to theend plate51.The inner end of the shaft is supported in a suitable seat in the'endplate 51, and is there provided with a thrust end bearingfas shown inFigure 1.' Upon the shaft 100 is formed aworm 104 which engages a wormwheel105 mounted upon the vertical shaft 36 journaled in bearings 1'07and 108 of the gear housing 103. The shaft 36 may be connected with anypreferred transmission mechanism such, for example, as the feedingdevices of a mining machine. a

In Figs. 1 and 4 of the drawings I have illustrated a preferred rotorconstruction wherein the drums 39 and 40 are built up of series ofsimilar discs 109, preferably about half an inch in thickness, which arestacked upon the shafts 42 and 43. These discs 109 are each providedwith a central circular aperture, adapted to fit closely upon the shaft,and are securely clamped between the collar 106 preferably formedintegral with the shaft, and the clamping rings 106a threaded thereto. Akey110 secures them against rotation relative to the shaft and eachcentral circular aperture is provided with four equally spacedkey ways111 each of which is fitted to the key 110. Formed on the periphery ofeach disc are gear teeth 112which may be of any'suitable form and r ofany preferred number which is indivisible V by the number of key ways111. In the example here illustrated I have provided fifteen teeth ofthe customary involute form. The relation of the gear teeth 112 to thekey way 111 is such that when assembling the discs upon the. shaft, therotation of each disc through one quarter of a revolution relative tothe next adjacent disc, will formspirally disposed zig-zag tooth bladeshaving a gencral inclination of approximately forty-five degrees to aline drawn parallel with the axis of the rotors; These'spirally disposedzigzag tooth blades are arranged to diverge from the transverse centralplane of the rotors towards its ends and to extend around approximatelyone-fourth of the circumference of the rotor. When such rotors aremounted in the casings 37 as above descrlbcd,

these spirally disposed tooth blades of one rotor intermesh with thoseof the other rotor and co-operate with the contacting surface 58 of thecasing to form V shaped expansion chambers 59 as above described. Shouldthe number of teethformed upon the periphery ofeach disc be other thanfifteen, or should the number of key ways in each disc be other thanfour, it is apparent that the angle formed between the resulting spiraltooth v blades and the longitudinal lines of the rotor would bedifferent from-that here illustrated,

in which case the circumferential extent of the contacting surface 58 ofthe casing would be made to conform to the spiral advance ofthe gearteeth of the rotors. I I

It is to be understood, however, that I do not limit'myself to theconstruction above described, andin Fig. 6 of the drawings haveillustrated an alternative construction wherein each rotor is composedof two metallic cylinders 113 and 114 keyed to the shaft and clamped inplace between the collar 106 a and the clamping ring 106m Upon thecylinder 113 is formed a plurality of lefthand spiral gear teeth 115each ofwhich extends from GIld tO end of the cylinder and around aboutone-fourth of its circumference.

Uponthe cylinder 114 is formed similar right hand spiral gear teeth 116extending from end to end of the cylinder and around about cumferenceofeach as above described.

worm 104 and worm wheel 1.05, may be omitted. In such case the shaftextension 42a may be removed from the shaft 42, a clamping member 47substituted. for the 1. In an engine of the class described, the vcombination with arpair of drums provided with a plurallty oflntermeshing zigszag gear,

tooth pistons and corresponding grooves diverglng 1n helical lines fromthe centralplane of the drums and each extendlng over a portion of thecircumference to the endsthereof,

of a casing having a wall in close proximity on the inlet-side only wlththe top of the gear teeth and'cooperating therewith to produce sets ofexpansion chambers, a port in said casing for admitting vfluid at themeeting point of the successive grooves and gear tooth pistons duringthe rotation of the drums, an open ended. elongated exhaust port in saidcasing wall spaced from said admission port inthe direction of rotationof the drums and extending. longitudinally from end to end thereof, andclearance space at both ends of said drum auxiliary to said exhaust portas and for the purpose set forth.

2. In an'engine of the class described, the combination with a pair ofdrums having a. plurality of intermeshing gear tooth pistons andcorresponding grooves diverging in helical lines from the central planeof the drums and each extending over a portion of the circumference tothe ends thereof, of a casing having a wall in close/proximity on theinlet side only with the tops of the gear teeth and cooperatingtherewith to produce sets of expansion. chambers, said wall extendingover a part of said drums equal to the circumferential advance of thetooth pistons, a port in said casing wall for admitting fluid at themeeting point of the successive grooves and gear tooth pistons duringthe rotation of the drums, and an open ended exhaust chamb'er extendingthe entire length of the drums and across their ends as and for thepurpose set forth.

3. In an engineof the class described, the combination with a casing, ofa pair of rotors having intermeshing spirally disposed tooth blades,each rotor consisting of a shaft having a longitudinal key upon which isstacked a plurality of discs, a central circular aperture in each discadapted to fit upon the shaft and provided with a relatively smallnumber ofkey ways, a relatively large number of gear teeth which isindivisible by the number of key ways formed upon the periphery of eachdisc, each disc being advanced one key way space beyond the nextadjacent disc thereby producing a relation of'gear eeth to forn spiraltooth vanes upon the resulting drum.

I l. In an engine of the class described, the combination with a casing,of a pair of rotors having internieshing spirally disposed tooth blades,each rotor consisting of a shaft having a longitudinal key upon which isstacked a plurality of disks, a central circular aperture in each diskadapted to fit upon the shaft and provided with a relatively smallnumber of key ways, a relatively large number of gear teeth formed uponthe periphery of each disk, each disk being advanced one key way spacebeyond the next adjacent disk hereby producing a relation of gear teethto form spiral tooth vanes upon the resulting drum.

5. In an engine of the class described, the combination with a pair ofdrums having a plurality of intermeshing gear tooth pistons andcorresponding grooves, of a casing having a wall in close proximity onthe inlet side only with the tops of the gear teeth and cooperatingtherewith to produce sets of expansion chambers, said wall extendingfrom p the meeting line of the drums in the direction of rotation over aportion less than half the circumference of the drums, supply devicesincluding control means to, alternately admit and cut off the flow ofexpansive fluid to wards said expansion chambers, an admission chamberbetween the control means and the expansion chambers, and means toprevent the fluid pressure within the admission chamber falling below apredetermined limit.

6. In an engine of the class described, the

combination with a pair of drums having a plurality of intermeshing geartooth pistons and corresponding grooves, of a casing having a wall inclose proximity on the inlet side only with the tops of the gear teethand cooperating there-with to produce sets of expansion chambers, saidwall extending from the meeting line of the drums in the direction ofrotation over a portion of the circumference of the drums, an exhaustchamber positioned opposite said casing wall and extendinglongitudinally of said drums from end to end thereof, supply devicesincluding control means to alternately permit and cut off the flow ofexpansive fluid towards said expansion chamber, an admission chamberbetween the control means and the expansion chamber, and automaticallyacting means to equalize the pressures in said exhaust chamber and saidadmission chamber when the supply of expansive fluid is out off.

7. In an engine of the class described, the

combination with a pair ofdrums having a plurality of intermeshing geartooth pistons and corresponding grooves, of a casing having a wall inclose proximity on the inlet side only with the tops of the gear teethand cooperating therewith to produce sets of expansion chambers, saidwall extending from the meeting line of the drums in the direction ofrotation over a portion of the circumference of the drums, an exhaustchamber positioned opposite said casing wall and extendinglongitudinally of said drums from end to end thereof, supply devicesincluding control means to alternately permit and cut of the flow ofexpansive fluid towards said expansion chamber, an admission chamberbetween the control means and theexpansion chambers, and automaticallyacting means to connect said admission chamber with the ex- Y ternalatmosphere when the supply of expansive fluid is cut off.

8. The combination of a casing having concave walls, a plurality ofrotors having intermeshing blades mounted in said casing with theirblades in substantially air tight relation with the walls thereof on theinlet side only, fluid pressure control means for admitting and cuttingoff fluid pressure to said rotors, and a second fluid pressure controlmeans to admit fluid pressure to said rotors on the inlet side uponcessation of pressure from said first mentioned control means.

9. The combination of a casing having concave walls, a plurality ofrotors having inintermeshing blades mounted in said casing with theirblades in substantially air tight relation with the walls thereof on theinlet side only, fluid pressure control means for admitting and cuttingofl fluid pressure to said rotors, and a normally closed valveoperableautomatically upon cessation of fluid pressure from said firstmentioned control means to admit fluid pressure to the inlet side ofsaid rotors.

11. The combination of a casing having two fluid pressure inlets, aplurality of rotors mounted in said casing with their blades insubstantially air-tight relation with the walls thereof on the inletside only, fluid pressure control means for one of said inairtight tothe teeth of said rotors on the inlet side, fluid pressure meansdelivering to a chamber between said partition wall and the wall of thecasing, and a secondnormally closed fluid pressure inlet delivering tosaid chamber, said second inlet having an inlet valve operableautomatically to open said inlet and admit pressure to the chamber uponreduction of pressure therein to a predetermined limit.

15. In a machine of the class described, an open casing divided by acurved partition wall having a fluid pressure inlet port into a closedfluid pressure chamber and an open rotor chamber, a pair of rotorshaving inter meshing teeth fitted substantially airtight on the inletside to said curved partition wall, a fluid pressure inlet for saidfluid pressure chamber on the opposite side of said curved wall, and asecond fluid pressure inlet for C said fluid pressure chamber providedwith a normally closed valve, which is automatically operable onreduction of pressure to alpredetermined limit in said fluid pressurechamber to admit pressure thereto.

In testimony whereof I affix my signature.

' NILS D. LEVIN.

lets, and a second fluid pressure control means for the other of saidinlets to admit fluid to said casing upon drop of fluid pressure at thefirst named inlet.

12. The combination of a casing having two fluid pressure inlets, aplurality of rotors mounted in said casing with their blades insubstantially air-tight relation with the walls thereof on the inletside only, fluid pres sure control means for one'of said inlets, and asecond fluid pressure control means for the other of said inletsautomatically operable to admit fluidto said casing upon drop of fluidpressure at said first named inlet.

13. In a machine of the class described, the combination of a pair ofrotors having intermeshing teeth, a casing having a curved wall providedwith a fluid pressure inlet port and fitted substantially airtight tothe teeth of the rotors on the inlet side and having an open exhaustchamber on the outlet side of said rotors, a fluid pressurechamberadjacent said curved wall and delivering to said fluid pressureinlet port, means for delivering pressure to said fluid pressurechamber, and a second normally closed pressure delivering meanscommunicating with said fluid pressure chamber, said second pressuredelivery means being operative automatically to deliver pressure to saidfluid pressure chamber upon reduction of pressure therein to apredetermined limit.

14;. In a machine of the class described,

the combination of a pair of rotors having intermeshing teeth, an opencasing enclosing said rotors, a curved partition wall having a fluidpressure inlet port fitted substantially

